Hi Debi –
Praying Mantis egg cases can take 6-8 weeks of warm temperatures, 65-75 degrees daytime, no lower than 45 degrees at night, to hatch. If immediate release is inconvenient you can keep the egg case(s) in the refrigerator for up to one week, but they must be in a ventilated container. DO NOT FREEZE.
To release, simply tie the praying mantis egg case(s) to twigs or branches about three feet above the ground. Birds and rodents will feed on them, so placing them in a container with holes large enough for the mantis to escape — 1/4 to 1/2 inch diameter — will provide protection.
To speed up the hatch, we recommend placing egg cases — still in the bag — on top of a refrigerator, or some place that is consistently warm, but not hot. Do not place them on a windowsill as temperatures fluctuate too much.
Note: Tiny praying mantis nymphs will emerge through the narrow slits of the egg case. Unless you can find the small nymphs (1/8 inch), it is impossible to tell if the egg cases have actually hatched — the egg case will NOT change in appearance.
If thereโs no sign of the nymphs after 6-8 weeks, please feel free to contact us. Here is a link to our website for more information on praying mantis: http://www.planetnatural.com/product/praying-mantis-egg-cases/.
Hope this helps!
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